It is fair to say that The Late Hector Kipling is a little late. When it was written, seven years ago, the Royal Academy's Sensation exhibition was scandalising New York, Tracey Emin's knicker-strewn bed was scandalising London and the Turner Prize was scandalising everyone - promoting conceptualism above true creativity and supposedly misrepresenting our country's talent.

But perhaps this is the perfect distance from which to look back in wonder. The angry young Brit Artists who were causing such a sensation are now the elder statesmen of the British art scene and those who have survived through the years have, despite all early conjecture, gained a credibility greater than some of their more traditionally minded colleagues.

Enter actor David Thewlis, known to older fans for notable appearances in Mike Leigh's Naked and Life Is Sweet, and to a younger audience as the lycanthropic Professor Lupin from the Harry Potter films. The Late Hector Kipling, his debut novel at 44, extends his considerable versatility still further. Thewlis has taken the turn-of-the-millennium London art scene and eviscerated it and the resulting gore makes for wonderful entertainment.

The novel opens in Tate Modern, where successful painter Hector Kipling is strolling with his considerably more successful best friend, conceptual artist Lenny Snook. Their friendship has always been competitive but Lenny's recent nomination for the Turner Prize (for a blood-filled limousine and a green, motorised coffin) has tested Hector's limits.

He has a burgeoning career, a beautiful, devoted girlfriend and loving parents who admire his work and sing his praises from the safety of their sofa in Blackpool. But for Hector, there is no pleasure in his achievements unless it is in relation to the achievements and failures of others, most notably Lenny. 'This young French couple ask if they can have their photograph taken with Lenny ... Lenny goes all bashful in his red leather coat-jacket, china-blue buttons, puts his arms around their shoulders and indicates that they should hand their camera to me. I take it. That's what I do.'

Hector's reaction is to cut off their heads in the photograph, able to manage his jealousy only through pointless destruction. As he becomes increasingly misanthropic, Hector is envious that Lenny is lucky enough to have a dead father, while he himself has no such character-building bereavements to enrich his art. So when their friend Kirk is diagnosed with a brain tumour, the potential attention it might bring Hector is irresistible.

As Lenny prepares his piece for the Turner exhibit, Hector descends into ever more dramatic self-destruction, a decline that accelerates when, in an event heavy with rather obvious symbolism, a motorcyclist accidentally drives through his face in a much-awaited self-portrait he was about to reveal.

This is a funny and successful satire of the contemporary art world, but at its core, it is a novel about the over-indulged and fragile artist's ego, about insecurity, about the darker layers of human relationships. Lenny Snook, despite his many pretensions, is a decent and considerate friend, but is none the less the undeserved subject of the unpleasant Hector's rabid, frothing rage. Thewlis has written with a black and cynical honesty about the triumph of bitter competitive destruction over our own will to succeed, as most around us aspire not simply to do well, but to do better as we stumble.

The plot is a little jerky at times, slow to get going, and then rather too speedy as it slides into farce in the final third. But following the unsympathetic Hector to his grand finale, played out in the galleries of Tate Modern, is a hilarious and horror-filled descent and definitely worth the wait.